1. Field of Invention
The present invention relates to a light-channeling apparatus and method. More particularly, the present invention relates to a light-channeling tube capable of preventing light dispersion and shielding against outside sources of light interference.
2. Description of Related Art
Following the rapid progress in computer capability and the development of Internet and multimedia technologies, the transmission of documents and images has become an essential element in communication. Textual information or image patterns are captured by a peripheral device such as an optical scanner and then converted into digital data by an analogue/digital converter. The digital data is transferred to an image file that can be displayed, identified, edited, stored or output.
In general for a scanning system, the light source and the first reflecting mirror of a scanning module are exposed outside a scanning module and hence this is one of the major factors that affect scan quality. In other words, most of the light from a light source projected onto a document must be redirected onto the scanning region after reflection and the document image must be shielded against interference from external light sources so that the image is able to project onto the first reflecting mirror. Both are critical factors that determine the ultimate quality of the image as captured by the scanner. FIG. 1 is a schematic diagram showing the position of a light source 120 and a first reflection mirror 130 inside a conventional scanning module 100. As shown in FIG. 1, the light source 120 is installed inside a light source carrier 118 on a body casing 110. The first reflecting mirror 130, a second reflecting mirror 132, a third reflecting mirror 134, a lens 140 and a light-sensing device 150 is are enclosed inside the body casing 110. Viewed from the top, the light source 120 and the first reflecting mirror 130 underneath light passage slit 112 can be easily seen. The light source 120 is, for example, a daylight lamp having a long edge similar in length to a document 160. The slit 112 has a sufficient width that permits light reflected from the document 160 to project onto the first reflecting mirror.
The light source 120 must project a line of light onto the document 160 to form a scan line there. To prevent the dispersion of light, most scanning systems have a collimating lens 122 installed above the light source 120 so that light from the light source 120 is focused on the document 160 to form an intense scan line. Although the lens 122 focuses light from the light source 120, there is no guarantee that light will not be dispersed to the surrounding regions.
Similarly, there is no facilities facility around the slit 112 that prevents stray lights from external sources from projecting onto the first reflecting mirror 130 and interfering with the quality of the reflected light coming from the document 160. Ultimately, quality of the image may be affected.